Non-Chrome Pretreatment Flight Demonstration

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Non-Chrome Pretreatment Flight Demonstration

• Progress ReportJill Ullett, PhD, SK
  TechnologiesJoe Osborne, PhD, Boeing

USAF Corrosion Program ConferenceMacon,
GA13-17, March 2006
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Background

• USAF Goal eliminate chromates by 2009

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What is Boegel/ AC-131?

• Boegel is Boeing Developmental name
• Licensed to AC Tech
• AC-131 (painting), AC-130 (bonding)
• Mixed Zr/Si oxide system
• Silane coupling agent chosen to match primer,
  sealant, or adhesive chemistry
• AC-131/Boegel-EPII is epoxy functionalized
  epoxy primers/adhesives
• Boegel-AM is amino functionalized polyimide
  adhesives
• Water solution -- 3-5 solids
• Spray on, no rinse, ambient dry
• Little or no waste
• Neutralize and sewer
• Superior adhesion
• Aluminum, titanium, CRES
• Common surface preparation
• pigmentable for corrosion protection and
  optical properties

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Program Objectives

• Phase I Laboratory validation of performance and
  process complete
• Phase II Flight test, targeted lab work
• Coat test vehicles complete Nov 2004
• 6 month and 12 month inspections complete
• Phase II Lab work focusing on
• Performance with aged substrate - complete
• Performance with non-chrome primers
• Performance with bi-metallic couple
• Optimization of paint stripping

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Phase I Performance

• Performance of AC-131 systems equivalent to
  coating systems with chromate conversion coating
  (CCC)
• 3000 hr slat spray corrosion
• Adhesion (tape and HATE)
• Filiform corrosion
• No impact on previously painted surfaces
• Useable for repair
• Requires scuff - sand

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Paint Application Nov 2004
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Paint Trial OC-ALC, March 2005

• Supported paint trial at OC-ALC
• One side of article treated with AC-131
• Paint systems for KC-135, E-3, and B-52 evaluated
• Test article aged outside, stripped and repainted
• Adhesion tests done at different stages

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Application Lessons Learned

• Graco pole gun, model 287023, for the
  application of AC-131BB was demonstrated in March
  2005 at Tinker Air Force Base and found to be
  very efficient.
• The pole gun is intended for use with barrel
  pumps or airless sprayers and is rated for use at
  pressures up to 3600PSI.
• Based on OC-ALC evaluations, paint stripping
  after aging is a concern. Primer takes more time
  to remove from AC-131 treated side versus
  conventional CCC.

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12 month Inspection (Nov 05), F-15

• AC-131 side showed paint loss at engine inlet,
  vertical stabilizer
• Some loss of adhesion of ceram coat on wing
  leading edge

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12 month Inspection, F-15

• CCC treated side showed slightly less wear at
  leading edges
• Overall coating on both sides in good shape
• A/C was scheduled for touch-up in Jan

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12month Inspection (Feb 06), KC-135
AC-131 side
AC-131 side
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12month Inspection, KC-135
CCC treated side
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Lab work

• Galvanic corrosion test panels
• Non-chrome primer evaluations
• Paint stripping optimization

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Alternate Process Scheme
Low Risk

• Alkaline clean / brighten / AC-131 / PrimePaint
• Eliminates chromate conversion coating
• Reduces rinse water (no rinse after
  AC-131/Boegel)
• Meets current engineering requirements
• detergent clean / AC-131 / Prime Paint
• Eliminates chromate conversion coating
• Eliminates brightener step and associated rinses
• Shows promise need to define cleaning process

Stretch Goal
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Scheduled Tasks

• Complete Lab evaluations
• Complete 18 month flight evaluation with final
  inspection
• Complete Final Report
• Draft TO 1-1-8 update

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Acknowledgments

• Project funded by ASC/AASS
• Project coordinated with ACC, AMC, AFRL, AFCPCO,
  WR-ALC, OC-ALC
• Project managed by SK Technologies
• Project Technical Management Boeing
• Thanks to paint crews at WR-ALC, OC- ALC, and
  BASC and to maintenance personnel at Eglin and
  Hickam